This invention relates to an assembly for fastening a layer of compressible material to a rigid member such as a layer of insulation to a roof deck and, more particularly, to an assembly which includes a metal fastener such as a screw projecting through the center of a resilient disk. The screw projects through the compressible layer and is threaded into the rigid member so that the head of the screw holds the disk down against the compressible layer. In the case of a roof, a waterproof membrane covers the insulation layer as well as the disks.
Uplift forces such as may result from wind tend to lift the insulation and the disk and this appreciably reduces the effectiveness of prior disks in holding the compressible layer down. Also, with prior assemblies, a downward force such as may be caused by walking on a roof causes the disk to slide down on the screw with the result that the membrane often is punctured by the screw head.